The effect of some non-nutritional factors on urea level in milk of Polish holstein-friesian cows

Summary.

The aim of the study was to investigate the effect of selected non-nutritional factors on urea content in milk of Polish holstein-friesian black-and-white cows. It was shown that the lactation group, the stage of lactation and actual daily milk yield do not have a significant effect on urea content in milk of analysed cows. In contrast, a statistically significant dependence was found between urea content in milk and both somatic cell count (at p ≤ 0.01) and the genetic group of animals (at p ≤ 0.05). The highest urea content was recorded in milk containing the lowest number of somatic elements and that coming from cows with the highest share (> 87.5%) of HF genes in their genotype.